Alkyl, ethenyl esters of pinic acid and polymers thereof



United 5...... PM. 0

3,063,970 ALKYL, ETHENYL ESTERS 0F PINIC ACID AND POLYMERS THEREOF Glen W. Hedrick, Lake City, Fla., assignor to the United States of America as represented by the Secretary of Agriculture I No Drawing. Filed Apr. 25, 1960, Ser. No. 24,635

' 29 Claims. (Cl. 260-785) (Granted under Title 35, US. Code (1952), see. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to alkyl, ethenyl esters of pinic acid, methods for producing the same, and to certain polymeric derivatives thereof. More particularly, the inplished in a selective manner according to the process of our invention to produce high yields of the half ester in which the acetic acid moiety of pinic acid is esterified. It has also been discovered that half saponification of either symmetrical or mixed dialkyl pinates preferentially saponifies the ester group of the acetate portion of the diester. Thus, it is possible by the processes of the present invention to prepare substantially any of the pure alkyl half esters of pinic acid. These pure alkyl half esters of pink acid can be readily esterified, either by direct esterification with a suitable alcohol or via the acid chloride, to produce pure mixed dialkyl pinates or pure symmetrical dialkyl pinates. The pure alkyl half esters of pinic acid can also be readily converted to the corresponding vinyl alkyl pinate by vinylation and vinyl acetate using a vinyl interchange method.

The following schematic diagram shows in general how the various pinic acid esters mentioned above are provention relates to monoand dialkyl pinates, vinyl alkyl duced according to our invention:

0 G7 ()l o 0&8 crrcon c in d Pimc Acid l? 9 g 9 ROC cucoa HO H 601;

Monoalkyl Pinate (3-carboxycyclobutane l'orm) Symmetrical Dialkyl Pinate .1! a U Q NaOH $5, Ste/5 (VIII) 9 0 O O 0 Vinyl 0 O n n R'OC cur'ioacu.=tzu ot zcn,oa Rot"; cu. .tio cu=cu. ROC crncou ca 21 ys Mixed Dinlkyl Finale Vinyl Alkyl Pinata Vinyl Alkyl Pinatc Mouoalkyl Pinata (vinyloxycarbonyl form) (vinyl acetate form) (acetic acid form) i .a r. A0 5 '3 (IX) a "'2? a: g

a a 9 e R'OC CH .(JOH ROC CILCOH NaOH ROC (.l-LLOR Monoalkyl Pinatc (acetic acid form) pinates derivable therefrom, divinyl pinate, and polymers prepared from these vinyl esters.

A primary object of the present invention is to provide methods of reacting the two carboxyl groups of pinic acid selectively and independently, to preparepure monoand mixed pinic acid esters. A further object of .the ods for preparing at will either half ester of the dibasic pinic acid, that is the -carboxycyclobutane form of half are useful for the selective synthesis and amides of the acid, including polyamides and polyesters. Other objects are to provide novel vinyl alkyl pinates, their homopolymers, and copolymers of the vinyl alkyl pinates with vinyl chloride; and to provide divinyl pinate useful in the preparation of polymeric materials.

I Direct monoesterification of commercially important dibasic organic acids like adipic acid and azelaic acid is not selective, a considerable portion of these acids being converted to diester during the esteritication. We have found, however, that due to the unique structure of pinic acid, direct monoesterification of this acid can be accom- Monoulkyl Pinate (acetic acid form) Mixcd Dialkyl Pinata Diagram pinic acid to produce the monoalkyl pinates (3 -carboxycyclobutane form) (rereaction by azeotropic distillation. It is usually desirable to continue the esterification until the reaction is substantially complete as indicated by acid number determinations. Following completion of the esterification reaction,

the isolation and recovery of the monoalkyl pinate can be accomplished without difiicultyusing conventional procedures such as phasic separations, distillations and the like. In the preferred procedure, the cooled reaction mix ture is-first washed with water to'remove the catalyst and then, to avoid formation of emulsions, is adjusted to a suitable alkaline pH by thc addition of a buffered aqueous alkali solution, prior to removal of any dieste'r Adjustment to case of the lower monoalkyl pinates. In the case of higher monoalkyl pinates, such as the Z-ethylhexyl and the hydronopyl monoesters, the pH should be maintained at about 9.5 to 10, and the amount of dilution controlled so that about 1 liter of water and 1 liter of solvent are present for each mole of pinic acid charged, to avoid the formation of stable emulsions. (The sodium salts of the higher monoalkyl pinates are particularly good emulsitiers; at a pH of 7, very stable emulsions are formed). The diesterfree aqueous solution is then acidified, and the resultant monoester product is isolated and distilled in vacuo in the conventional way.

The other type of monoalkyl pinate, i.e. the acetic acid form, can be produced by several routes according to our invention. This type half ester can be produced from conventional, symmetrical dialkyl pinates (by reaction VII of the diagram), or from mixed dialkyl pinates (by reaction V or X of the diagram). Each of the three aforementioned half saponification reactions can be readily carried out by reacting equimolar quantities of the particular dialkyl pinate and alkali in a suitable unreactive solvent until the half-saponification reaction is substantially complete. his generally preferred to employ ethanol as the-solvent, and sodium hydroxide as the saponifying alkali. It is usually desirable to heat the reaction mixture to speed up the saponification. A reaction temperature of about 70 C. is generally adequate. Following completion of the half-saponification reaction, the isolation and recovery of the monoalkyl pinate (acetic acid form) can be accomplished using conventional procedures such asphasic separations, distillations and the like. A preferred procedure is to remove the solvent under reduced pressure, dilute the reaction mixture with water, remove any unreacted diester by extraction with an organic solvent, then acidity the aqueous phase with mineral acid and extract the monoester with a suitable solvent, such as ether or benzene. After removal of solvent, the mouoester product is vacuum distilled in the conventional manner. volumes and alkalinity during the extraction of unreacted diester, as described above for the preparation of the monoalkyl pinates (3-carboxycyclobutane form) by direct monoesterification of pinic acid, to avoid the formation of stable emulsions.

In addition to having useful emulsitication applications, the two types of monoalkyl pinates prepared as described above can be used to prepare useful resin-forming monomers for polyesters, polyamides, or ester amides; to prepare pure mixed dialkyl pinates, and if desired the symmetrical dialkyl pinates; and to prepare novel vinyl alkyl pinates having utility in the production of polymers.

According to the present invention, various dialkyl' pinates can be prepared either by direct esterification of the appropriate monoalkyl pinate with the appropriate alcohol (reactions II and IX of the diagram) or by reaction of the acid chloride of the monoalkyl pinate with the appropriate alcohol (reaction III of the diagram). Symmetrical dialkyl pinates can be prepared by direct esterilication employing a monoalkyl pinate and an alco- 1101 having the same alkyl group (reaction II of the diagram). In carrying out the direct esterification (reac-' tion II or IX of the diagram) it is preferred to react equimolar quantities of the monoalkyl pinate and the Care must be taken to control the ity in the production of polymers.

appropriate alcohol in the presence of a suitable, unreactive organic solvent like benzene and a conventional esterification catalyst. The preferred catalyst is p-toluene sulfonic acid. it is preferred to conduct the esterilication at the reflux temperature of the reaction mixture, removing the water formed in the reaction by azeotropic distillation and continuing the reaction until it is substantially complete. Following completion of the esteriiication, the mixed dialkyl pinate can be readily isolated and purified using conventional methods. The preferred procedure is to wash the reaction mixture with water, then with dilute alkali, and finally with water; to remove the solvent; and then to distill the diester product in vacuo.

The mixed dialkyl pinates can be prepared by reacting equimolar quantities of the acid chloride of the monoalkyl pinate and the appropriate alcohol (reaction III of the diagram), in the presence of a suitable, unreactive organic solvent and an alkaline agent, such as soda ash, to absorb the hydrogen chloride liberated in the reaction. It is generally preferred to carry out the reaction at reflux temperature. After completion of the reaction, the reaction mixture is washed with water, stripped of solvent, and the diester product is vacuum distilled in the usual way. The mixed dialkyl pinates of the type produced by reaction III of the diagram, have a novel utility. The R group, introduced by monoesterification according to reaction I, can be from a cheap, easily obtainable alcohol. The R group, introduced subsequent to the R group, can be from an expensive, difiieult-to-obtain alcohol. Upon half saponification of the mixed dialkyl pinate (reaction V of the diagram), the resulting monoalkyl pinate contains the R group at the 3-carboxy position. This monoester can thereby be produced at considerable saving of ROH over what would be required if the conventional symmetrical dialkyl pinate (containing two R groups) is first produced and then half saponified to yield the same monoalkyl pinate.

Vinyl alkyl pinates are produced according to the present invention by vinylating either the B-carboxycyclobutane form of monoalkyl pinate (by reaction IV of the diagram) or the acetic acid form of monoalkyl pinate (by reaction VlII of the diagram). The preferred method is to vinylate the monoesters with vinyl acetate using a conventional vinyl interchange procedure. It is generally preferred to employ a large stoichiometric excess of vinyl acetate, and to carry out the vinylation at about room temperature in the presence of a copper resinate polymerization inhibitor and a mercury salt of a strong acid as catalyst. After the vinylation reaction is completed, the excess vinyl acetate is preferably removed under reduced pressure at a temperature between about 20 and 30 C. The crude, vinyl acetate-free ester is then dissolved in ether or some other suitable organic solvent, and treated to remove catalyst and any unreacted monoester by washing with dilute aqueous mineral acid, then with dilute aqueous sodium hydroxide buffered to pH 8 to 9 with sodium carbonate, and finally, with water. The aforementioned washing procedure is desirable, since it decreases the still residue. After the washing is completed, the solvent is stripped and the vinyl alkyl pinate isolated by vacuum distillation according to conventional procedures.

The novel vinyl alkyl pinates of this invention have util- These vinyl esters homopolymerize readily to yield homopolymers having low softening points. Homopolymers of various molecular weights can be produced. The vinyl alkyl pinates copolymerize readily with vinyl chloride to yield copolymers of a variety of compositions. These copolymers are rigid plastics, which can be processed at lower processing temperatures than those required for processing the conventional poly(vinyl chloride-vinyl acetate) copolymers.

The following examples are given by way of illustration and not by way of limitation of the invention.

EXAMPLE 1 Monoalkyl Pinates (Acetic Acid Form) by Half Saponification of Symmetrical Dialkyl Pinates 2,2- dintethyl 3 (ethoxycarbonyl)cyclobulaneacetic acid.-Diethyl pinate, 800 g. (3.3 moles), prepared by conventional direct esterification of pinic acid, was dissolved in 1 liter of 95 percent ethanol. To this a solution consisting of 132 g. (3.3 moles) sodium hydroxide dissolved in 132 ml. water was slowly added while stirring. The reaction mass warmed to' about 70 C. and the pH changed from about 14 initially to between 7 and 8 at the end of the reaction. The ethanol was removed under reduced pressure and the residue was diluted with one to two liters water. The unreacted diester was extracted with ether or benzene and isolated by evaporation of the with sodium carbonate. to avoid formation of stable emulsions. (Since the sodium salts of these higher monoalkyl 'pinates are particularly good emulsifiers, maintaining the aqueous phase at a pH of 7 is unsatisfactory. and leads to the formation of very stable emulsions.) When benzene was used as the solvent the extraction was carried out hot. In all cases removal of the neutral, unreacted diester facilitated separation of the residual components. The extent of saponification and yield was independent of the diester used. The composition of each of the monoalkyl pinate products was calculated from neutralization and saponification equivalents. The physical and chemical characteristics of the various monoalkyl pinates are given in Table I. All of these esters exhibited a strong absorbance in the infrared at 7.5 microns, attributable to the presence of the alkoxycarbonyl group in the esters.

TABLE I.MONOALKYL PINATES (ACEIIC ACID FORM) O 0 Composition, percent Neutral Sapohifiration H I H o -l equivalent equivalent Refractive ROC 01200021 Hg indg x Density an a b! c Calcd. Found Calcd. Found D 128 0.2 100 214.3 214.3 107.1 107.1 1.4509 1.0730 142 0.25 2.4 97.6 0 242.3 233.2 120.2 120.1 1.4588 1.0407 171 0.15 0 90.0 10.0 203.4 331.0 155.3 154.8 1. 4554' 0. 90m 202s 0. 0.8 99.2 0 336.5 330.3 166.8 105.1 1. 4907 1.0572 a=Pinic acid. b=Monoester. c=Dlest 2r. 1 Theoretical S.E. calculated from N .13. found.

solvent. Diester recovered was g. (10 mole percent). EXAMPLE 2 wi mi er laci and i aqueous phase was acldlfied a d Monoalkyl Pmates (3-Carboxycyclobutane Form) again extracted as above to remove pinic acid and monob Direct Monoesterification ester. The combined extracts were dried over anhydrous sodium sulfate, the solvent evaporated and the residue 45 Ethyl 2,2-dimethyl 3 (carboxy)cyclobulaneacetate;

distilled in vacuo using an 18 inch Vigreux column. The distillate when seeded with pure 2,2-dimethyl-3-(ethoxycarbonyl)cyclobutaneacetic acid gave a solid mass of crystals. The yield of monoester was 565 g. (80 mole percent), n.e. 214, and of pinic acid, B.P. 163-l65 C. (0.2 mm.), was 61.5 g., 10 mole percent. Separation of the products of the saponification by distillation was considerably easier when the diester was removed as described.

The physical and chemical characteristics of the monoester (2,2 dimethyl 3 ethoxycarbonylcyclobutaneacetic acid are given in Table I.

2,2 dimethyl 3 (rz-butoxycarbonyl)cyclobutane acetic acid; 2,2-dimethyl-3-(2-ethyIhexyloxycnrbonyl)- cyclobutaneacetic acid; and 2,2-a'imethyl-3-(hydronopyloxycarbonyl)cyclabutaneacetic mini-These three monoalkyl pinates were prepared by half saponification of di-n-butyl pinate, di-Z-ethylhexyl pinate, and dihydronopyl pinate, respectively, using the same general procedure and ratio of reactants employed above for preparing the monoethyl pinate. In preparing the Z-ethylhexyl monoester and the hydronopyl monoester, one liter of solvent and one liter of water were used per mole of ester charged, and the aqeuous phase was maintained at pH 9.510 10 by addition of 1 N sodium hydroxide buffered 6 N-butyl 2,2-dimethyl-3-(cnrbaxy)cyclobutaneacetate; 2- etlzylhexyl 2,2-dimetl1 'l-3-( carboxy cyclobutaneacetate; and hydronopyl 2,2-dimethyl-3-( cnrboxy cyclabutaneacetate.These four monoalkyl pinatcs were prepared by refluxing 186 g. (1 mole) of pinic acid and one mole of the appropriate alcohol in 480 ml. benzene containing 6 g. p-toluene sulfonic acid. When all the water from the reaction had been removed azeotropically and the acid number indicated the reaction was complete, the mass was cooled and washed with water to remove the sulfonic acid. Some of the unreacted pinic acid was removed in this wash. The batch was made alkaline by adding approximately 1 N sodium hydroxide bufiered with sodium carbonate, care being taken to control the volumes and alkalinity for this extraction as described for the half esters of Example 1.

The diester-free aqueous solution was acidified and the monoester distilled as described in Example 1. The properties and data obtained from characterization of the monoesters are tabulated in Table II. In every case the saponification and neutral equivalent are in agreement, thus establishing the composition reported. None of thes monoesters were found to absorb in the infrared at 7.5 microns as did the alkoxycarbonyl derivatives of Example 1.

TABLE II.-MONOALKYL PINATES (Ii-CARBOXY CYCLOBUTANE FORM) O 0 Composition, percent Neutral saponification H i H MmJ equivalent equivalent Refractive ROC CH2COR B.P., C. Hg lndge x Density d" n a 1 b l c 1 Calcd. Found Calcd. Found n 135 0. l. 0 0 214. 3 214. 3 107. 1 107. 0 1. 4533 l. 0706 139. 5-144 0. 3 0 99. 5 0. 5 242. 3' 243. 6 121. 3 120. 2 1. 4590 1. 0462 174 0. 17 11. 6 S8. 4 0 298. 4 237. 4 139. 4 139. 1 1. 4569 1. 0090 199 0. 1 i 7. 2 92. 8 0 336. 5 283 159. 0 158. 2 1. 4899 1. 0652 l a =Pinlc acid. b: lt lonoester.

c=Dlester. 1 Theoretical S.E. calcd. from N .13. found.

The acid chloride was prepared from the monoethyl pinate of Table II using thionyl chloride. The acid chloride, when added to liquid ammonia in ether, gave a liquid amide, 13.1. 154 C. (0.3 mm), n 1.4817, Anal: c lcdfor C11H1903N1 N, 6.57.

- 8 dialkyl pinate product, 266 g., 71% yield, B.P. 180 to 182 C. (0.1 mm.), with 32 g. still residue. An 86% yield of mixed diester was obtained with n-butyl alcohol. EXAMPLE Monoalkyl Pmates (Acetic Acid Form) by Half Found: N, 6.57. S1m1larly, amides prepared from p-nitroaniline, p-aminobenzoic acid and ethylenediamine Sapomfimmn of Mixed Dmlkyl Pmales were all liquids The n-butyl, Z-ethylhexyl, and hydronopyl half esters EXAMPLE 3 of Table 1, Example 1 and of Table ll, Example 2, were vin lated to oduc the res ectiv mixed vi1 l alk 1 Mixed Dialkyl P1114168 Fro"! Manual/(Y1 Fina!" pin tcs and t ll; lattzr were feduce d to give ilz e Sar e The mixed dialkyl inateshaving the structures and mixed dialkyl pinates depicted in Table 111, Example 4. properties indicated in Table III, were prepared by re- These mixed dialkyl' pinates were subjected to half action of the acid chloride of the monoalltyl pinate with saponification with sodium hydroxide according to the the appropriate alcohol. procedure described in Example 1. In each instance, TABLE III.MIXED DIALKYL PtNA'ms Ethyl 2,2-dimethyl-3-(alkuxy- Saponillcatlon N carbonyl) eyelobutaneaoetatcs Rch-nc- Density equivalent 0 o B.P., C. MmJHg tlvo inglex d up g l g Gated. liound R=n-Buty1 116 0.3 1.4470 0.0901 135.2 133.2 2-ethylhexyl- 151. 0.3 1.4519 0.9610 163.2 162.4 Hydronopyl..." 181 -0.1 1.4194 1.0201 152.3 184.0

Alkyl 2,2-d'1methyl-3-(ethoxy carbonyl) cyclobutaneaeet-ates i l i cmtodQorncoa The following procedures are illustrative of the the major product produced was substantially pure acetic methods employed in making the mixed diestcrs of acid form of monoalkyl pinate having the general struc- Table III. ture given in Table I, Example 1. These experiments Alkyl 2,2-dimetI1yl-3-(eI/zoxycarbonyl)cyclobmaneestablish the configuration of the alkyl pinates with acetares by direct esterification.-2,2-dimethyl-3-(ethrespect to the location of the alkyl substituents. Details oxycarbonyl)cyclobutaneacetic acid, 78.7 g. (0.367 of typical experiments are as follows: mole), prepared as described in Example 1, was estcrliDfied H lf sa amfimtion of Butyl 2,2-Dimethyl-3-(Ezh with hydronopyl alcohol, 61.8 g. (0.367 mole) in encarbonyl)cyclobutaneacemle Zeno, 200 ml., with gm. p-toluene sulfonic acid as a Butyl .2,2 dimethy1 3 (elhoxycarbonyl) cyclobutarw x g g g g g fracugns i: acetate, 20.28 g., upon half saponification gave: (1) 0.8 3 a 5 g., B.P. to 126 c. (0.15 mm.), {1.6. 212.2, CZllCd, for fI'Z CtIOB, g., B-P. 181 mm), Wltl'i 5 g Still monoehyl pinata g Bl)- to 0 C. $35 'g ifeg f gzzf a few dIOPS methyl 0.15 mm.), n.e. 209.8 and 3 1.2 g., B1 136 to 160 r ,1 e C. 0.15 .,..l9.3. h t' 0- Since the amount of the Catalyst in F was ethyl este i i r i ea c tfof uese 5215;2 3: 932 9 8f2 $131 L less than 3 f gf 94.2 percent, respectively. Assuming a normal 80 perg g g 2 3 2 3 3 1 jggz gg 3525: g g g cent conversion of diester to monoester obtained in a number of instances, a calculated yield of 12.84 g., was pftoluene Sulfomcv and 3 fonoWmg fracnons S g expected. These distillates contained only monoester obtamed: 103 to 140 and pinic acid. The yield of monethyl pinate was 11.97 F 9' BID-140 to 246 igi g. or 93.4 percent of the expected quantity. Each of the pgncl gallly 1C5. gisgrrgggzng lggryig Thesefrargtrons when1 seeded with pured2,2 l1methyl-3-(ethoxy i i car on c c o utaneacetic a ave sol'd mass 0 fractions were principally diethyl pinate, hydronopyl 2,2- Crystal: y g a 1 1 53222 31 2222??igzgggg and Half Saponification of Ethyl 2,2-Dimelhyl-3-(nBut0xy- Ethyl 2,2-dimetl1yI-3-(alkoxycnrbonyl)cycl butaneace- F h f fg q gzgg h 1 7 rates by use of acid chl0rider.-n-butyl and hydronopyl 3 a bsapom 5 of 1 of et i i' alcohols were reacted with ethyl 2,2-di1nethyl3-chlorofi y uwxycar i zx gf g g g i carbonylcyclobutaneacetate, prepared by reacting the g Ions 2 t ethyl 2,2-dimethyl-3-(carboxy)cyclobutaneacetate of Ex- 5 2 3? b P 4 2 E; 2 8 12 e ample 2 with thinoyl chloride. A typical example using 23 1 and (3) 2.0 g., B.P. 144-150 C., (0.15 mm.) hydronopyl alcohol 1s as follows. one mole of alcohol (168 g) was dissolved in 500 m1 benzene in which 56 n.e. 224.3. The concentrations of monobutyl ester were 96.2, 98.1 and 95 percent resp. The 12.86 g., of monog. soda ash was kept suspended by agitation. The acid b 1 h 2 h l b 1 hloride 232 g 1 mole) was added dropwise while 76 my 5" mi/carbon glowing the fiction mass at reflux temperature A cyclobutaneaceuc acid, obtained was 38.6 percent of the small amount of water distilled which was collected in expected amount ggi f percent Converslon' a decanter. After washing with water and stripping the solvent the product was distilled. There was a forecut. Vinyl AlkylPmaieS 12 g., B.P. 103 to 178 C. (0.25 mm.) and the mixed Vinyl 2,2-dimethyl-3-(ethoxycarbonyl)cyclobutaneacemm.); (2) 50.1 g., 87.5 to 96' rate (by Reppe process).2,2-dimethy1 3 (ethoxycarbonyl)cyclobutaneacetic acid, 214 g. (1 mole), and zinc oxide, 15.7 g. (0.19 mole), were added to 250 ml. toluene and heated to reflux to remove water by trapping in a decanter; The solution was almost clear, although some of the zinc salts remained undissolved. Glacial acetic acid, 13.8 g., was added to completely clarify the solution.

The toluene solution was charged to an Aminco rocking type autoclave of 1 liter capacity, heated to 120 C.,

flushed three times with nitrogen, and finally left under.

100 pounds nitrogen pressure on the equipment. Acetylene was added to full tank pressure ofB'Ji) lbs. The Hatch was heated to 180 C. Acetylene absorption was complete in 4 hours. The autoclave was allowed to cool, the contents removed. washed with dilute sulfuric acid, water and dilute carbonate solution. The toluene was stripped under water-aspirator vacuum and theresidue was distilled using a 24-inch Vigreux column. Thefollowing fractions were obtained: (1) 5 ml. 20 to 37.5 C., (0.4 (0- 52 a 97 C., (0.5 mm.) to 99 C., (0.55 mm). Five ml. of the 2nd and 3rd fractions polymerized violently when 0.3 percent benzoyl peroxide was added, indicating the formation of polymers from the vinyl esters. Both polymers were insoluble in acetone, benzene and methanol indicating crosslinking, presumably because of the presence of some divinyl pinate in the fractions.

Vinyl 2,2-dimethyl 3 (ethoxycarbonyl)eye-[abutmeacetate (by vinyl interchange reacrion).-2,2-dimethyl-3- (ethoxycarbonyl)cyclobntaneacetic acid, neutral equivalent 214, 455 g. (2.13 moles) was dissolved in 1193 g. (13.9 moles) freshly distilled vinyl actate containing 1.22 g. copper resinate. Mercuric acetate, 9.4 g. (0.029 mole), was dissolved therein while at room temperature, then 2.33 g. (0.023 mole) concentrated sulfuric acid was added slowly. The final solution was clear and bright green in color. After standing 72 hours, g. sodium acetate (0.12 mole) was added. The excess vinyl acetate was stripped by water-aspirator vacuum, maintaining the still msidne at a temperature of to C. The crude ester was dissolved in 500 ml. ether. This solution was washed with dilute aqueous sulfuric acid, then with two 500 ml. portions of water made alkaline, pH 8 to 9, with a small amount of a solution containing 2 percent sodium hydroxide and 1.5 percent soda ash, and finally washing with water. Acidification of the alkaline extract gave g. recovered starting material. Removal of the solvent under vacuum as above and distillation, bnlb-to-bulb, gave 431 grams, El. 100' C., 1.9 mm. to 1.5 mm., with 30 g., residue. Redistillation at 2 mm. using a 24-inch Vigreux column gave the following fractions: (1) 10 g. upto 106 C., (2) 72 g., 105 to 111 C., (3) 28 g., 111 to 112 C., and (4) 300 g., 112 C. l

The last three fractions were combined for removal of divinyl pinate by distillation through a 45 cm. column packed with extruded nickel. The composition and certain properties of the fractions of distillate collected are given in the following table:

Composition 1 Percent Fractions B.P.. 0., Weight, Hydro- 2 g. gestation A B equivalent 101-108 16 95. 1 4. 9 1. 97 108-111 17 Q5. 1 4. 9 1. 97 111 l1 1 l. l 88. 9 1. i1 111-113 4 1. 8 93. 2 1. 02 113 21 1. 4 9.; u 1. 01

1 Calc.,m (A) divinyl pinata, (B) vinyl ethyl pinate 1 Determined by hydrogenation in acetic acid SORIQUB with 5 percent palladium oncarbon catalyst.

No-m.-Residne,55g. Y

Fractions 4a through were combined and the small amount of divinyl ester remaining therein was removed by distillation, using the nickel packed column at a high reflux ratio.

The remainder of the charge was distilled at a more rapid rate. A sample of fraction 4:: and samples of the final distillate (pure 7 below) were polymerized as the initiator. The polymers 10 with added divinyl pinate vinyl 2.2-dimethyl-3-(ethoxycarbonyl)cyclobutaneacetate, characteristics and properties given in Table IV below), added divinyl pinate (prepared with and without 2 percent as described in Example in bulk with benzoyl peroxide from 40 and the sample were not soluble in benzene, is apparent that some divinyl pinate is produced by this vinyl interchange reaction in addition to the major product, the vinyl allzyl pinate.

.Vinyl 2,2dimethyl3-(n-butoxycarbonyl)cyclobumneacetate and vinyl 2,2-dimethyl-3-(2-elhylhenl0.rycarbonabove for vinylating the With the higher molecular vinyl acetate charged was ester 644 g. (7.48 moles) and with the 793 g. (9.22 moles) vinyl pinate ester.

accomplished by the vinyl interchange procedure used 3-ethoxycarbonyl derivative. weight esters the volume of increased. With the butyl Z-ethylhexyl ester acetate were used per mole The properties of the two resultant vinyl alkyl pinates are given in Table IV below.

Because of the higher boiling point of these higher molecular weight vinyl alkyl esters, it was easier to free them pinate than in the case of the vinyl ethyl ester.

of divinyl Ethyl, n-Imtyl, 2-ethyllrexyl and hydronapyl 2,2-dimethyl 3 (vinylox carbonyl)cycI0butaneacetates.-

Vinylation of ethyl, n-butyl,

Z-ethylhexyl and hydronopyl 2,2-dimethyl-3-(carboxy)cyclobutanencetates by reacting the respective mono esters with vinyl acetate as above r snltcd in to percent yields of the vinyl alkyl pinates.

The quantity of vinyl aceta le employed was increased for the higher molecular weight esters, as described above.

The properties of these fou 40 in the lower half of Table r vinyl alkyl pinates are given 1V below. The following results are from a typical vinylation of 454 g. (2.12 moles) of the ethyl pinata, yieldin g 413 g. of crude ethyl vinyl pinate which distilled as follows:

4;) H Composition 1 I: Pc ":1. Hydro- Fracuons 13.1. C., eight, 5 common 2mm. g. equivalent 5310104 2;) E to 112 43 T. G 93. 4 1. 0:3 112 it) 113 45 l. 2 '33. S l. 012 113 27) g 0.8 99.2 1.009

I Calcd. as (A) divinyl pinata. (B) ethyl vinyl pinata.

The presence of the 5m in the above fractions was i data.

TABLE I'm-VIN all amount of divinyl pinate ndicated by the hydrogenation ALKYL 'IINATES (Vinyl acetate iorm) llydm- Boiling 60 .eL-napoint tin n n n z: R H /l a G. rnmJ 0c crr.c OC H=CH: Hg

B.=Ethyl 0.99 113 20 1. 4558 1. 020 6a n-Bntyl 0. 99 1354; 2. 0 l. 4559 9902 0. 98 142 0. 4 l. 4594 9591 (V inyloxyearbonyl form) 0 0 ll I ll 70 CHFCHOC CHzCOR R==Eth'yI 1.009 113 2. n 1. 4556 1. m n n-Butyl (I. 09 1304 2, 0 1. 4560 9930 Z-ethplhcxyl... 1. D07 13% 0. l l. 45.92 9580 7 Hydmnopyl 1. 004 0. 1 1. 1872 1. 0127 identical with the respective mixed dialkyl pinates of Table III, The diethyl pinate was identified in similar manner. These results confirm that the configuration of the vinyl alkyl pinates withrespect to the location of the vinyl and alkyl substituents is as depicted in Table IV.

EXAMPLE 7 Divinyl pinate.Pinic acid, 82 g. (0.44 mole), was vinylated using the vinyl interchange reaction, as described for the vinyl interchange preparation of vinyl 2,2- dimethyl-S-(ethoxycarbonyl)cyclobutanencetate in EX- arnple 6. The crude divinyl pinate was isolated without use. The general procedure for making the homopolymers was as follows: g. of vinyl alkyl pinate, ml. of water, 0.5 g. of a commercial sodium alkyl aryl polyether sulfate, 2 ml. of a 2.5% by weight aqueous solution of potassium persulfate, and a drop of lauryl mercaptan were charged into a 2-02. polymerization bottle. The bottle was flushed with nitrogen, sealed with a cap containing a rubber gasket, and then tumbled end-over-cnd in a 50 C, constant temperature bath for the period of time indicated in Table V below. Any minor variations in the recipe are noted in Table V. The resulting polymer latex was coagulated in the usual way with sodium chloridesulfuric acid-water coagulant solution. The coagulated polymer was then dissolved in benzene and precipitated by pouring the solution into methanol. The polymer was separated and freeze-dried under vacuum to give the final homopolymer product. The results of a number of homopolymerization experiments are given in Table V.

TABLE V.-HOMOPOLYI\IERIZATION OF VINYL ALKYL PINATES Polym- Con- Capillary Expcrlerizaversoftening Inherent Monomer merit tion sion, Range, viscosity 1 Minor variations in recipe No. time, Per- C.

hrs. cent Vinyl ethyl pinata (vinyl acetate form, Table IV) l 48 so 80-100 0. 48 Coagulated with saturated NaCl so ntion.

2 48 70 80-100 0.63 Emulsion freeze dried and polymer reprecipitatcd.

3 48 60 78-105 1 ml. of 5% KzSgOs solution.

4 67. 5 70 70-107 0. 62 g. monomer, 20 ml. water, 2.6 g. of a commercial sodium alkyl nryl polyeth er sulfate, 4 1111.0! 2.5% KzSzOs solution.

Vinyl ethyl pinata (vinyloxycarbonyl form, Table IV)--- 5 24 75 65400 0.58 1 g. of a commercial sodium alkyl aryl polyether sulfate, 1 ml. 5% K25 0; solution.

24 70 68- 92 0. 60 1 ml. of 5% KgOzSs solution. 12 80 68- 95 0. Do. 48 80 S0- 90 0.60 .2 ml. 01' 1% K2520: solution. 48 10 86 0. 38 1 ml. of 1% K2520! solution.

Vinyl 11 butyl pinate (vinyl acetate form, Table IV) 52 80 68 86 0. 73

Vinyl 11 butyl pinata (vinyloxycarbonyl form, Table IV) 52 70 64- 84 1. 20

72 77 0.81 20 g. monomer, 20 ml. water, 4 ml. 2.5%

K SgOa solution.

Vinyl 2 othylhexyl plnnte (vinyl acetate form, Table IV). 13-.-" 90 90 14 96 0.47 20 g. monomer, 20 ml. water, 2.5 g. of

o commercial sodium alkyl oryl polycther sulfate, 4 ml. of 2.5% K 810; solution.

Vinyl 2ethylboxyl plnste (vinyloxycariionyl form, Table 48 50 041 IV). 16 90 65.5 0.38 20 g. monomer, 20 ml. water, 2.5 g. of n commercial sodium alkyl oryl polyether sulfate.

hydronupyl plnnte (vlnyloxycarbonyl form, Table 17 168 50 80 0.17 Double recipe.

I 0.25 g. Homopolymor per 100 ml. benzene solvent at 25 C.

I Homopolymer-AnaL calcd. for C limOt: C, 64.98; H, 8.30; found: C, 64.51; H, 8.31. I H0rnopolymer-AnaL mind. for C llmO C, 04.08; H, 8.39; iouml C, 65.13; H, 8.48. 4 Homopolyrner-Annl. cnlcd. or 01512 0,: C, 07.13; H, 9.02; found C} 60.61; H, 9.17. Homopolymer-Annl. caled. for 0 5112.04: C, 07.13; 11, 9.02; found: C, 67.00; H, 9.16. 8 Sticky polymer; almost lluid at room temperature.

7 Homopolymcr-Anal. calcd. for 0 0K 0 C. 70.33; H 9.94; found: C, 69.60; H, 9.75.

8 Conversion could not be measured because of sticky e of the Homopolvmer-Anal. calcd. for CwlisgOt: C, 70.33; 11, 9.

polymer. 4; found: C, 69.62; H, 9.75.

W Hoinopolymer-AnoL cnlcd. for 6231134042 0, 72.89; H, 9.45; iounc: O, 72.75; H, 9.59.

. washing to remove the catalyst and acidic components.

A total of 30 g. (0.126 mole) of pure divinyl pinate was obtained by a bulb to-bulb distillation and finally distillation using an 18 inch column packed with A; inch glass helices. It had the following characteristics: boiling point l10ll2 C., 2 mm; n 1.4667; d 1.0343; hydrogenation equivalent, 1.99, The divinyl pinate was reduced, and the resulting diethyl ester was identified as diethyl pinate by its boiling point (108 l 10 C., 1 mm), refractive index (r1 1.4457), and density (d 1.0123).

EXAMPLE 8 Homopolymerizations Homopolymers were made from each of the seven vinyl alkyl pinates of Table IV, Example 6, the esters being f -hly redistilled under reduced pressure prior to Copolym erizations The vinyl alkyl pinates of Table IV, Example 6, used for the homopolymerizations of Example 8, were also found to copolymerize readily with vinyl chloride to produce copolymers of a variety of compositions. The general procedure for making the copolymers was as follows: A polymerization bottle was charged with the desired weight of vinyl alkyl pinatc monomer. water (20 '14 were prepared for evaluation of their mechanical characteristics, several -bottles were charged and polymerized at one time and the contents combined and worked up together. The results of a number of ,copol'ymerization ml), a commercial sodium alkyl aryl polyether sulfate 5 experiments are given in Table VI.

TABLE VL-COROLYRIERIZATION OF "INYL ALKYL PINATES WITH VINYL CHLORIDE Vinyl Polynl- Conver- Soltcn- Inherent Chlorine Ester Experl- Vinyl alkyl pinate, type ester G. chloride, erizatlon slon, ing i \'U5" plum-rat lllt'nrpoment No. g. time, percent range, ity 1 percent. mtion, 0. percent Vinyl ethyl pinate (vinyl acetate form) 2 18 $1 34 148-170 0. 77 52- 7. 4 m 88 65 137460 e. 1 47. 71 16. 0 d0 4 16 64 26 138-158 0. 72 50. 07 11. 8 do. 4 16 88 78. 5 130-155 0. 92 46. 82 17. 5 do 6 14 88 14 122-152 0. 82 42. 59 25. 0 do 6 14 88 34 120-152 0. as 42. 16 as. 7 Vinyl ethyl pinata (vinyloxymrbonyl iorm) 2 18 96 18 175-185 0. 71 52. 79 7. 5 d0 4 16 72 48 128-150 0. (i9 48. 00 15. 5 d0 4 16 72 48 130-144 0. 70 47. 84 15. 8 d 4 16 88 60 125-155 0. 79 47. 44 16. 4 do 4 16 168 .86 135-105 0. 03 40. 82 17. 5 d0 6 14 87.5 71 120-140 0.64 41.00 27.8 6 14 88 75 123-148 0. 79 41. 09 20. 1 10 6 14 88 87. 5 124-155 0. 9'7 41. 79 26. 4 Vinyl n-hutyl pinate (vinyl acetate l'orm) 4 1G 88 55 134-152 0. 78 48. 52 14. 5 16 4 16 88 57 130-158 0.82 43. 58 14.4 17 m 4 16 88 73 1125-158 0. 93 47. 01 17. 1 18 1 d0- 6 14 88 82 20-147 0. 73 42. 81 24. 5 9 Vinyl n-bntyl pinate (vinyloxycarbonyl form) 4 16 88 67 137-152 0.7 48. 35 14. 8 0 a 0- 6 14 88 65 135-157 0.01 43.91 22.6 21 (lo 0 14 88 71 130-153 0. 91 43. 28 23.7 22. Vinyl 2-ethyll1exyl pinate (vinyl acetate lorm) 4 16 168 84 130-157 0. 73 4& 44 14. 0 23 5 m 6 14 168 72 120-148 0. 89 4-4. 01 21. 4 24 do-.- 6 14 16B 87 125-142 0. 75 41. 98 26. 0 25 Vinyl Z-Qthylhexyl pinata (vinyloxycarbonyl form) 4 1B 88 21.5 125-153 0. 74 51. ll 10. 0 2'3 d0--- 4 16 168 78 132-155 0. 71 40. 51 1S. 0 27 do 6 14 168 89 135-153 05 42. 1G 25. 7 28 d0 6 14 108 73. 5 130-152 0. 7 41. 80 2G, 4 29 Vinyl hydronopyl pinate (vinyloxyearbonyl form) 6 14 168 54 135-151 0. 55 40.1 17. 8 30 d 6 14 168 5'] 138-158 0. (i5 '10. 1G 18. 0

I Measured at a concentration of 0.25 g. i Copolyrners produced in (2.5 g.), potassium persulfate'solution (2 ml. of 2.5% solution) and a drop of lauryl mercaptan. The bottle was flushed out with nitrogen and cooled in a'Dry Ice-acetone bath. Then an excess of liquid vinyl chloride was added and the bottle allowed to warm up sovinyl chloride distilled out of the bottle until the desired weight remained. The bottle was then tightly capped and after it had warmed up to room temperature was placed in a 45 C. bath and tumbled end-over-end for the time noted in Table VI below. The bottles were then removed, cooled and opened. The latex was coagulated with salt-sulfuric acid solution. The polymer was collected, washed well of polymer in 100 ml. 01 tetrahydrolnrnn at 25 C these experiments were used in tests to evaluate their mechanical characteristics (see. Table V11 bclowi.

Selected copolymers of each type produced in the experiments reported in Table VI were tested for their mechanical characteristics, using standard test procedures. The results of the tests are given in Table VII below. ASTM tests 638-521 were employed to determine all the characteristics of the copolymers given in Table VII, except for the torsional flex temperature (T,) which were determined by ASTM Test D 10435 1. The copolymers were rigid plastics. It was possible to process them at lower processing temperatures than those required for processing the conventional poly (vinyl chloride-vinyl acetate) copolymers.

TABLE VII-MECHANICAL CHARACTERISTICS OF COEQJEIELIERS OF VINYL ALKYL PINATES WITH VINYL OHLO Tensile strength at break, psi. C 01 t 1 M d h Milling htleoldlng Yleltd Mpdulus Etlon- 5P op ymero viny c ori evrit temp, n1p poiu e elas- 2:: ion, 0.

igmal Cross C. p.s.1. t1eity cross some percent section at break Vinyl ethyl pinate (vinyl acetate form) 1 270 280 7, 800 205, 000 4,870 8,440 29 Vinyl ethyl pinata (vinyloxycarbonyl lorm) 270 280 7, 730 205.000 4, 580 7, 920 19 +55 Vinyl n-bntyl pinata (vinyl acetate form) L-.- 290 290 7, 070 187, 000 4, 340 7,200 11 +52 Vinyl n-bntyl pinate (vinyloxyearbonyl form) 4 270 $0 7, 490 192, 000 5, 380 10, 300 138 +54 my] Z-ethylhexyl pinate (vinyl acetate form) 5 250 260 6,800 174,000 4, 710 S, 160 22 +46 Vinyl 2-ethylhexyl pinate (vinyloxycarbonyl torm) 250 260 6,470 150,000 5,260 5 9,950 139 +42 Vinyl hydronopyl pinate (vinyloxyearbonyl form) 1 290 290 8,150 203,000 4,990 7,200 12 +61 1 Equal parts by weight of copolymers from Experiments 5 and 6, Table VI, blended for use in these tests. 1 Equal parts by weight of eopolymers from Experiments 12, 13, and 14, Table VI, blended or use in these tests.

I Copolyzuer from Experiment 18, Table VI. 4 Equal parts by weight 5 Copolymer nom Experiment 23, Table VI.

of copolymcrs from Experiments 20 and 21, Table VI, blended for use in these tests.

6 Equal parts by weight of copolymers from Experiments 27 and 28, Table VI, blended for use in these tests. 1 Equal parts by weightot eopolymers from Experiments 29 and 30, Table VI, blended for use in these tests.

with water, methanol and ether, and then dissolved in tetrahydrofuran to give about a 10% solution. This solu- We claim: 7 1. A pinale of the formula CH CH; 3 0 11-0-6 Z-ethylhexyl.

wherein R and R' are radicals selected from the group consisting of vinyl and alkyl, either of said R and R being vinyl when the other is one of said vinyl and alkyl radicals. 1k2.1 The pinate of claim 1 wherein R is vinyl and R is a y v 3.1 The pinate of claim 1 wherein R is alkyl and R vmy i 4. The pinate of claim 1 wherein R is vinyl and R'is 5. The pinate R is vinyl.

6. The pinate of claim 1 wherein R is vinyl and R is hydronopyl.

7. The pinate of claim 1 wherein R is hydronopyl and R is vinyl. 15

8.1Thepinate of claim 1 wherein R and R are both vmy 9. A process comprising esterifying pinic acid having the formula of claim 1 wherein R is Z-ethylhexyl and m agent with an equimolar quantity of an alcohol having the formula ROH wherein R is an alkyl radical to form the 3-carboxycyclobutane form of the half ester of pinic acid having the formula OHi CH; CH (I) O HO- CHz-LQ-B wherein R has the same significance as above, isolating said half ester, subjecting the half ester to vinyl interchange to produce a vinyl alkyl pinate having the formula OH; CH;

0 ll CHFGH-O-O CHr-LO-R wherein R has the same significance as above, isolating the diester, saponifying the diester to form the acetic acid 60 form of the half ester of pinic acid having the formula C H; CH;

wherein R has the same significance as above, isolating said half ester, subjecting the half ester to vinyl interchange to produce a vinyl alkyl pinate having the formula CH CH:

wherein R has the same significance as above, and isolating the vinyl alkyl pinate.

aoeaeaq' .7 I 13: The process of claim 12 wherein R is 2-ethylhexyl. 14. The process of claim 12 wherein R is hydronopyl. 3 15. A pr I ess comprising subjecting pinic acid having the formula c O LZQHPLOH to vinyl interchange to produce divinyl pinate having the o mula,

v OH: OH;

and isolating the divinyl pinate.

16. A process comprising esterifying pinic acid having the formula i,

with an equimolar quantity of an alcohol having the formula ROH wherein R is an alkyl radical to form the B-carboxycyclobutane form of the half ester of pinic acid having the formula 0H: CH;

0 I HO- Hr- 0-3 wherein R has the same significance as above, isolating said half ester, esterifying said half ester with an alcohol having the formula ROH wherein R is an alkyl radical to form the diester of pinic acid having the formula OH: OH;

O t IV-(P g wherein R and R have the same significance as above, isolating the diester, saponifying the diester to form the acetic'acid form of the half ester of pinic acid having the formula CH: C

0 R0 -iIJ OH:I 011 wherein R has the same significance as above, isolating the acetic acid form of the half ester, subjecting the acetic acid form of the half ester to vinyl interchange to produce a vinyl alkyl pinate having the formula CH; CH;

wherein R has the same significance as above, and isolating the vinyl alkyl pinate.

17. A process comprising esterifying pinic acid having the formula I OH:- O- CH=C H:

with an equimolar quantity of an alcohol having the formula ROH wherein R is an alkyl radical to form the 3-carboxycyclobutane form of the half ester of pinic acid having the formula O CHr-iE-OH OH: CH3

0 o no-ii I om-b-o-n wherein R has the same significance as above, isolating 18. A homopolymer of a pinate of claim 1. said half ester, converting said half ester to the acid 19. A homopolymer of the pinate of claim 4. chloride of said half ester, esterifying said acid chloride 20. A homopolymer of the pinate of claim 5. f the half ester with an alcohol having the formula 2l. A homopolymer of the pinate of claim 6. ROH wherein R is an alkyl radical to form the diester 5 A op y 0f the pinate of claim of pinic acid having the formula 23. A homopolymer of the pinate of claim 8.

CH1 cm a 24. A copolymer of vinyl chloride and a pinate of 0 0 Clainl 1- I l -J5 L V e 10 dag; Vcoeolymer of vinyl chloride and the pinate of wherein R- and R have the same significance as above, A 9P of inyl chloride and the pinate of acetic acid form of the half ester of pinic acid having the .ltin h claim5. so a g t e diester, saponlfymg the diester to form the 27. A copoiymer of vinyl chloride and the pinate of f ul claim 6. mm a 28. A copolymer of vmyl chloride and the pinate of o 0 claim 7. ll IA 2.?9. copolymer of vinyl chloride and the pinate of claim 8. I wherein R has the same significance as above, isolating Ref rence Cited in the file of this patent the acetic acid form of the half ester, subjecting the acetic acid form of the half ester to vinyl interchange to pro- UNITED STATES PATENTS duce a vinyl alkyl pinate having the formula v 9 5 Goldbfifg et p 26, 1969 Cm cm 2,970,168 Hornet a1. Jan. 31, 1961 (I) (I) OTHER REFERENCES RO-(. I H1-( J0-CH=CH= Lewis et al., Journal Organic Chemistry, vol. 24, 1870- 1872 1959). wherein R has the same significance as above, and isolat- Lewis et al., Journal Organic Chemistry, vol. 25, 623- ing the vinyl alkyl pinate. 625 (1960). 

1. A PINATE OF THE FORMULA 